ABSTRACT
Chronic obstructive pulmonary disease (COPD) is a condition characterized by chronic inflammatory airflow obstruction partially reversible with bronchodilator therapy. This anatomic condition causes expiratory flow limitation and dynamic lung hyperinflation leading to dyspnoea and exercise intolerance. The aim of this chapter is to examine the results of studies using two gas mixtures different from room air, supplemental oxygen and helium/oxygen (Heliox), to improve exercise tolerance in COPD. The rationale for the use of supplemental oxygen during exercise in these patients is to reduce the drive to breathe and thus lung dynamic hyperinflation and exertional dyspnoea. The rationale for Heliox relates to its reduced density compared to room air and its consequent ability to improve expiratory airflow, thus reducing lung dynamic hyperinflation and exertional dyspnoea. Both gas mixtures are expected to ameliorate exercise intolerance in COPD patients.
